Currently, there is little understanding of how shales fracture. At best, empirical models based on very simplified physics are used, but there is no way to relate geophysically observable properties of the shale to its geomechanical properties. Moreover, even given a geological model, there are also no computer models that can reliably predict the microseismic response of the shale fractures. Finally, existing methods of analyzing microseismic data utilize only a very small amount of the information in estimating the origin of the microseismic events.
A number of difficulties have led to such poor understanding of how shales fracture. Primarily, understanding shale fracturing requires compiling together a great deal of information. For example, the porosity and mineralogy of the shale may need to be known at multiple scales to understand shale fractures and the geomechanical response. Additionally, the coupled contributions of fractures, variable pore types, microporosity, and mineral heterogeneity to geophysical response in shale may need to be understood. Other difficulties lie in properly estimating the errors involved in predicting factures in shale and in the possibility that the data can have pronounced anisotropy, which would affect the accuracy in locating fractures in the shale. Some computational tasks (such as source scanning, modeling of synthetic waveforms, etc.), may be cumbersome and may require significant resources and time to complete.
Due to these difficulties, current stimulation techniques of areas having shale are based on little knowledge of how the shale is fracturing. Additionally, current production profiles merely indicate that active fractures in shale are at least 100 meters apart. In the end, such currently used techniques in the industry have low efficiency and use a protocol developed with only rudimentary knowledge of what is going on. In the end, operators are unable to explain or predict their results.
Because of the poor knowledge available in the industry about fractures in shale, more understanding about the fracturing of shale in an area of interest can increase both the reserves and production associated with the area. In fact, increases in both reserves and production may be possible by an order of magnitude if more accurate understanding about the fracturing of shale can be determined.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.